(1) Field of the Invention
The present invention relates to an optical data system and, more particularly, to an optical data link system for communicating information through a structure.
(2) Description of the Prior Art
There is a need to pass information between a first environment and a second environment while meeting safety requirements intended to prevent communication of fluids between the environments. The structure separating the environments can be a wall or a door. Of course, a passage can be created in the structure through which electrical wires and/or fiber cables can be fed. Such systems, however, suffer from limitations such as the potential exposure of the one environment to the conditions in the other environment through the passage. That is, movement of the wires and/or cables can break a seal between the environments.
As one example, U.S. Patent Publication No. 2011/0280538 discloses a pressure resistant media converter apparatus that utilizes a hermetic electrical feedthrough and a hermetic optical feedthrough. Electrical wires pass through the hermetic electrical feedthrough and optical fibers pass through a hermetic optical feedthrough. The feedthrough configuration, however, creates the situation where movement of the wires and/or fibers might break the hermetic seal and thereby exposing the inner chamber to the outer chamber conditions.
As another example, U.S. Patent Publication No. 2007/0003207 discloses a pressure transducer with an optical waveguide feedthrough assembly that interprets signals generated by sensors to allows real-time monitoring of the state of the feedthrough assembly. These sensors, however, monitor the state of the feedthrough assembly rather than a condition within an inner chamber.
A radio connection could be used in some environments for this solution; however, in many situations it is desirable to have a metallic structure separating the environments. These metallic structures are impenetrable to radio waves. It may also be undesirable to have radio waves within a structure because such waves could interfere with other operations within a structure.
One application requiring passage of information from one environment to another is in submarine operations. The exterior of a submarine hull can be subjected to liquid environments at much higher pressures than the gaseous environment on the interior of the hull. This often occurs with submarine launch tubes. The interior of the launch tube can be open to either the exterior environment or the interior environment. There are preexisting light pipes that allow visual inspection of the interior of a launch tube. Accordingly, it is desirable to transmit sensor readings from the interior of a launch tube to the exterior of the launch tube.
Thus, there is a need for an improved device for providing a data link through structure to communicate information such as, for example, a sensed condition in another environment, such as is identified in the present application.